- Mycotoxin Risk
- Gut Performance
- Mycotoxin Risk
- Gut Performance
Guide to Pig Management: Gilts (Part 1)
This six-part series looks at the different stages of the pig production cycle, covering good management and nutrition practices and offering BIOMIN solutions at each stage to help boost animal performance.27.05.2021
• Good gilt management can influence the future reproductive performance of the sow herd.
• Many management factors should be considered to optimize lifetime performance including housing, vaccinations, nutrition, and fertility.
• Particular attention should be paid to the wean-to-estrus interval for sows to ensure their full genetic potential can be realized.
Gilt management practices from birth have the potential to influence the future reproductive performance of the sow herd (Patterson and Foxcroft, 2019). Hughes et al. (2010) found that inadequate sow nutrition contributed to high culling rates, but the main problem was gilt management. It is therefore essential that the best management practices are used throughout the production cycle. Good gilt management can largely bridge the gap between excellent genetic potential and the more modest sow lifetime productivity typically achieved in the industry (Patterson and Foxcroft, 2019).
Good gilt management can largely bridge the gap between excellent genetic potential and the more modest sow lifetime productivity typically achieved in the industry.
The housing conditions of maiden gilts can affect both their short-term health and long-term productivity, yet gilts entering the farm are often housed in some of the poorest accommodation conditions. To ensure maximum genetic potential is fulfilled, important factors to consider include:
- hygiene: preventing excessive infection pressure
- thermal comfort: preventing extremes in temperature and sunburn, eliminating drafts
- lighting: providing 14 to 16 hours of daylight or equivalent artificial light to maximize stimulation of puberty and subsequent cycling
- boar contact: providing intermittent rather than permanent contact with mature boars (over 14 months of age). Direct contact with a rotation of mature boars reduces age at puberty. Early sexual maturity is linked with improved sow lifetime productivity (Patterson and Foxcroft, 2019).
- nutrition: a wide range of nutritional strategies have been advocated for gilts, and specialist advice should be sought. Always build in a period of quarantine or adaptation of at least 6 weeks.
Gilts are traditionally supplied to farms either as weaners (35–45 kg) or at full weight (90–110 kg). The choice will depend upon how long gilts are to be quarantined and acclimatized. If there is no quarantine, a minimum of six weeks from entry to service is advisable, with the aim of inseminating at a minimum of 225 days of age and 135 kg liveweight.
Space allowance should be at least 0.9 m2/head with a maximum of ten gilts per pen. Floors should preferably be fully, or half slatted and of a good quality concrete. Housing should be well ventilated, and the temperature curve should be between 16 and 20 °C. Floors should be kept dry, as wet floors reduce fertility.
Drinking water should be clean and fresh with a minimum flow rate of 2 l/min, preferably delivered through drinking nipples at a height of 50–65 cm, with one nipple per 10 animals. A mature gilt will drink an average of 16 liters of water per day (Table 1). Plumbing should be checked periodically and kept clean. Chlorine and acids disinfect pipes but do not clean them. Products are now available that remove the biofilm from the inside of pipes.
Table 1. Average daily water intake by different groups of pigs
|Group||Weight (kg) or period||Water consumption (l/day)|
|Suckling piglets||0 - 8||0 – 0.3|
|Weaners||8 - 25||1.0 – 2.5|
|Growers||25 - 45||2.5 – 4.0|
|Finishers||45 - 105||4.0 – 10.0|
|Sows||Gestation period||15.0 – 20.0|
|Lactation period||> 25.0|
The minimum direct/indirect light intensity should be 230–300 lux.
Vaccination protocols depend on the circumstances of the individual farm and can only be decided by the local vet based on regular site visits and an understanding of the disease situation both on the farm and in the local area. Gilts should not be vaccinated in the first weeks after their arrival. Depending on the health status of the farm, traditional vaccinations may include those against:
- PRRS (porcine reproductive and respiratory syndrome)
- SIV (swine influenza virus)
- E. coli
- PCV2 (porcine circovirus type 2)
- Glässer’s disease (Haemophilus parasuis)
- atrophic rhinitis (AR)
- Actinobacillus pleuropneumoniae (APP)
Skipping the gilt’s first estrus has a positive effect on litter size, although there is no benefit in any further delay (Patterson and Foxcroft, 2019). The gilt should be a minimum of 235 days old and 135 kg in weight at first service. First inseminations are more closely related to weight than age, and 145–160 kg is the optimum range for higher total piglets born per lifetime and better longevity results.
Gilt nutrition should be distinguished from slaughter pig nutrition. The nutrient density of the gilt ration should facilitate a slower growth curve than fatteners by ad libitum feeding. Gilts should grow in a progressive and regular way, gaining 675–700 g/day. Sufficient nutrients should be provided while the sexual organs are developing. Vitamin and mineral provision during this phase should target tissue and bone development, and more bioavailable forms are recommended.
Gilts should be fed to a controlled schedule of high-low-high intake to provide the appropriate nutrition for body growth and estrus, preventing the liver from overload during the last third of gestation. Constipation at the end of gestation can be avoided by providing adequate water and fiber. Troughs should provide a feeding space width of 35 cm per animal. Feed types must be changed gradually.
Stimulating gilts and sows
Gilt feed rations should be increased during the two weeks before insemination by flushing with up to 42.5 MJ digestible energy (DE)/day, a process which helps to increase the quantity and quality of ovulation (Anderson and Melampy, 1972).
In sows, the crucial period is the wean-to-estrus interval (WEI). This is when the sow has just finished lactating and will have lost body condition, regardless of the duration of lactation. The sow will need an immediate supply of energy because estrus depends on light intensity and energy. Light intensity must be 250–300 lux at sow head or eye level for a minimum of 8 hours, although 16 hours is preferable.
Energy intake must be high, so lactation feed may need top-dressing with sugar twice a day. Insulin levels peaking twice a day favors the onset of estrus. Including fish meal at 1 kg/t feed is also recommended. WEI is a great indicator of sow condition after weaning and depends on how much the sow has been able to eat, the size of her litter, and the season. An average WEI is around 5.5 days; any shorter could mean that feed intake during the last week of lactation was high, and any longer could indicate a shortage of energy. Sows should be accommodated in quiet conditions, in individual crates with dry floors. At least two boars are recommended to stimulate estrus.
The following factors have an impact on reproduction:
- Environment: floor, ventilation, light, season, temperature, drafts
- Management: animal husbandry, timing and method of service, equipment, hygiene, transport, handling, mixing, confinement, feed composition including vitamins and minerals, feeding method and schedule, water supply and toxins such as mycotoxins or xenoestrogens
- Viral diseases: including PRRSv, parvovirus, PCV2, SIV, Salmonella, Streptococcus
When fertility is at stake, any clinical investigation must consider many factors and signs to make an accurate diagnosis and propose an effective solution.
The three golden rules of sow husbandry are quiet, hygiene, and routine.
Patience and professionalism are required during this important stage. Semen must be collected and stored properly, using the appropriate tools and a suitable extender. Insemination must be carried out correctly, ensuring that there is good standing reflex. The complex interaction between embryos and uterus means that sows should not be moved (to minimize stress) or mixed (to minimize risk of infection) in the two weeks after insemination to avoid interrupting the early establishment of pregnancy, which would reduce conception rate and litter size (Almond, 1994).
Almond, G.W. (1994). When (not) to move your sows. Proceedings of the North Carolina Healthy Hogs seminar. Greenville, NC. 2nd November 1994.
Anderson, L.L. and Melampy, R.M. (1972). Factors affecting ovulation rate in the pig. In: Cole, D.J.A. (ed.) Pig production. London: Butterworths, 329-366.
Hughes, P.E., Smits, R.J., Xie, Y. and Kirkwood, R.N. (2010). Relationships among gilt and sow live weight, P2 backfat depth, and culling rates. Journal of Swine Health and Production 18(6). 301–305.
Patterson, J. and Foxcroft, G. 2019. Gilt management for fertility and longevity. Animals. 9(7). 434.